1. Field of the Invention:
The invention relates to folding tool bars with hinged wing members which are operable between folded transport positions and extended operative positions.
2. Description of the Prior Art:
The prior art has revealed various folding tool bar arrangements with extensible wings wherein the wing members are operative between two positions, with the wings locked in fully-extended position or locked in a fully-retracted position. Certain of these include lost motion connections to enable some degree of wing movement responsive to ground contours but without provision for locking the wings against such movement.
U.S. Pat. No. 3,693,724 relates to a mechanism for folding and locking disk harrow gangs which utilizes a hinge lock arrangement including a hinge lever 35 with an integrally-formed hook 39 that engages a hinge bracket 25 when the hydraulic cylinder 25 is extended to lock the extension beam 21 in extended position.
U.S. Pat. No. 3,713,495 is for an automatic disk harrow hinge locking device and reveals a hinge locking arrangement for positioning a disk harrow arm and wherein the locking member 32 automatically moves into locked position under the inpetus of a torsion spring 41.
U.S. Pat. No. 4,061,195 covers a lock and lift mechanism for a foldable implement and shows a hinge lock which includes a reciprocating pin 48 to lock the wing in extended position by engaging the pin into the housing 54.
U.S. Pat. No. 4,074,766 relates to a floating folding tool bar having a lock means and includes a lock device to lock a tool bar wing in a vertical position for transport and which includes cooperating lock parts on the wing member and the hydraulic operating cylinder.
U.S. Pat. No. 4,316,511 for an implement frame especially for agricultural machines discloses a lock mechanism to lock a wing in extended position and includes a latch member 9 that is hydraulically actuated about the shaft 10 to move the wing member 3 to its extended position and lock the wing in that position through engagement of the hook 12 with the stop 13.
These patents fail largely because they do not provide mechanism that will lock the wing members in extended positions against movement relative to the central tool bar structure as well as to lock the wings in retracted positions and also provide means for free floating of the wing members in response to terrain contours.